In article <crawford-0201961220260001 at powerlarry.mib.uga.edu>,
crawford at bscr.uga.edu says...
>>In article <2814E93001B938D9 at office.mmc.org>, varyc.mmcri at mmc.orgwrote:
>>> Hi all,
>> Has anybody noticed a recent tendency for the Promega minipreps to
fail
>when doing large numbers of (bluescript) preps?
>> I originally thought it might have been due to evaporation of the EtOH
>from the wash solution but we've seen the problem with a new kit.
>> Previously we've had no problems.
>>>> Any thoughts greatly appreciated.
>>>> Cal Vary
>>>Our lab has had problems with these preps as well. We traced our
problem
>to the host strain. Ecoli strains which are endoA (JM 83, BL-21 etc)
>positive yielded miserable results in our hands. We have solved the
>problem and now get excellent results. If you would like further
>information plz feel free to e-mail me and I will explain
--
DH5(alpha) and XL1-bluse are recommended by Qiagen for this reason.
Also they have less carbohydrate I think. I would recommend switching to
the Qiaprep Spin Plasmid kit, they come out to about $1 per prep.
Promega kits also work much better with vaccuum than with spinning. If
you don't want to buy their "pig" you can rig up a sidearm flask with a luer
connector stuck in the top. But this isn't efficient though if you have more
than a few.
One other thought-- is someone new doing the preps and are they possibly
vortexing the lysates?
Jody K. Hirsh
Northwestern University, Chicago, IL. USA
jkh141 at nwu.edu